Mr Murdoch's kayaking group has joined forces with seven other conservation and outdoor recreation organisations to fight for New Zealand's wild rivers, which include the Nevis, to be protected from hydro-electric dams and irrigation intakes.
Their aim is to have legislation enacted that would give rivers the same level of protection as national parks.
"We've said enough is enough - too many wild rivers have been destroyed. We need to look after the few we've got remaining," Mr Murdoch (35) said.
The groups that united this week are Fish and Game, Federated Mountain Clubs, Forest and Bird, Whitewater NZ, the Council of Outdoor Recreation Associations of NZ, the NZ Rafting Association, the NZ Federation of Freshwater Anglers and the Environment and Conservation Organisations of NZ.
Over summer, they will be organising events to highlight the value of wild rivers.
They were spurred into action by plans for a hydro dam on the West Coast's Mokihinui River, irrigation water storage dams on Canterbury's Hurunui River and fears the Government is considering scrapping Water Conservation Orders nationwide, Mr Murdoch said.
"There's been a general growing of alarm among the NGO's about the threats to rivers."
Dams on five wild rivers in the North Island and six in the South Island are in the offing.
The New Zealand and Otago Fish and Game Councils have sought a change to the existing Water Conservation Order on the Kawarau River, asking for a ban on damming the Nevis River, along with conditions on minimum flows.
The Ministry for the Environment has appointed a special tribunal to determine whether hydro development on the Nevis should be banned.
The status quo would leave the option open for dams on the river.
A month-long hearing that began in Cromwell in May has been adjourned until early next year, when more witnesses will give evidence.
Having kayaked for 15 years and worked as a kayak and raft guide in Italy and Japan, Wanaka-based Mr Murdoch has seen the impact on rivers "where they are heavily modified by dams and irrigation structures".
His nearest wild river is so dear to his heart that he and partner Natalie Kerr gave their baby Maia, Nevis as her second name.
